My invention relates to an electric lighting fixture and in particular to a low voltage lighting fixture designed for outdoor use and constructed mainly of polyvinyl chloride resin.
In the past, for various reasons, most electric lighting fixture housings and fittings have been made of metal. One reason is that metals do not deteriorate or deform as the result of the high temperatures generated within a lighting fixture by the standard 110 volt lamps used in conventional lighting fixtures. However, for lighting fixtures designed for use out-of-doors, most metal housings and fittings are subject to rapid corrosion due to constant exposure to rain and sun and, in coastal areas, to salt spray, even when the metal parts are temporarily protected by paint. Moreover, recent increases in the price of steel and aluminum and in fabricating costs have resulted in increases in the prices of conventional lighting fixtures with housings and fittings made of metal.
The present trend to reduce energy consumption has resulted in increased use of low voltage lamps, that is, electric lamps which operate at voltages considerably less than 110 volts. These low voltage lamps, particularly 12 volt lamps, generate far less heat in operation than 110 volt lamps.
I have determined that it is possible to construct a very satisfactory outdoor lighting fixture for use with a low voltage lamp which has a housing and essentially all its components made of polyvinyl chloride resin. Such a lighting fixture is less expensive to manufacture and more durable than conventional outdoor fixtures.
Simply put, my unique lighting fixture comprises eight major components as follows: a cylindrical housing having at its center an interior annular ring preferably made entirely of white high density polyvinyl chloride resin (hereinafter often referred to as PVC); a low voltage electric lamp having an outer diameter slightly less than the inside diameter of the cylindrical housing; a lens having an outer diameter slightly less than the inside diameter of the housing; a pair of flexible O-rings for sealing the lamp and lens within the housing; an annular lens retaining ring preferably made of white PVC; a tubular conduit containing the electric wires connected to entergize the lamp; and a circular base plate preferably made of PVC for sealing the rear of the housing. The fixture may also include one or more spacer rings made of PVC for increasing the spacing between the lamp and the lens and/or the interior ring of the housing.
As assembled, an O-ring or preferably a spacer ring and then an O-ring are seated on the upper edge of the interior ring of the cylindrical housing and then the preferably 12 volt electric lamp is seated on the first O-ring. Next a second O-ring is seated on the upper outer surface of the lamp and then the lens is placed on top of the second O-ring. Then the annular lens retaining ring is firmly pressed onto the upper face of the lens and secured to the upper edge of the housing by stainless steel screws or other suitable means. The electric wires connected to energize the lamp are contained within a tubular conduit which enters the fixture through a hole in the center of the circular base plate that seals the rear of the housing.
Various modifications or additions can be made to the basic fixture just described. A light diffuser can be substituted for the lens retaining ring. A mounting bracket or swiveled stand can be added to the rear of the housing.
I am aware of a number of prior suggestions in the art to use various plastic and elastomeric resins in the fabrication of lighting fixture components. These suggestions include U.S. Pat. Nos. 3,902,057; 4,210,841; 4,360,862, 4,379,321; 4,380,793 and 4,414,613. However, my outdoor lighting fixture possesses the following advantages over conventional outdoor fixtures as well as over the devices shown in the foregoing patents:
1. Because most of its components are already available in quantity, the cost of its components is lower than the cost of conventional fixture components.
2. Because its eight components can be quickly assembled by unskilled labor, my lighting fixture costs less to manufacture than conventional fixtures.
3. Because it utilizes a low voltage lamp and its housing is contructed of white high density polyvinyl chloride resin, the housing will not deteriorate or deform in operation.
4. Because its housing and most of the fittings are made of white high density polyvinyl chloride resin, the fixture is literally impervious to the deleterious effects of sun, rain and salt spray even in tropical climates.